Means for forming a rigid loop from a limp loop



N- O YOUNG July 11, 1967 MEANS FOR FORMING A RIGID LOOP FROM A LIMP LOOPFiled Sept. 19, 1966 INVENTOR O. YOUNG NIELS Rw .S AA J L A TORNEYUnited States Patent C) 3,330,557 MEANS FOR FORMING A RIGID LOOP FROM ALIMP LOOP Niels 0. Young, Lincoln, Mass., assignor to Block Engineering,Inc., Cambridge, Mass., a corporation of Delaware Filed Sept. 19, 1966,Ser. No. 595,283 8 Claims. (Cl. 272-8) ABSTRACT OF THE DISCLOSURE Adevice having an ordinarily limp loop, part of the loop being disposedin a channel in a guide, and including means for driving the loopcontinuously through the guide at a high enough speed so that the loopwill become erected into a steady-state, rigid configuration.

This invention is a continuation-in-part of copending application Ser.No. 537,431 filed Mar. 25, 1966, now abandoned.

This invention relates to erecting systems and more particularly tomeans for and method of erecting a flexible, closed loop into asubstantially rigid structure.

Under ordinary circumstances, a flexible loop of material cannot assumea self-supporting configuration if it is completely compliant, i.e.lacks stiffness. The shape and size in which a flexible loop can beself-supporting depends largely upon the extent to which its degree ofstiffness opposes loading, such as would be due to gravity.

It has now been found that a compliant flexible loop moved along itselfprovides an appearance of mechanical stiffness and can thus be erectedto form a substantially rigid-appearing, self-supporting structurecapable of astonishing extension.

It is, therefore, a principal object of the present invention to providean erection system incorporating such a loop and operable to erect theloop into a substantially rigid-appearing elongated configuration.Devices incorporating the principles of such a system are quite simpleto manufacture and operate, and thus lend themselves readily to use astoys which provide sustained fascination and amusement to the user.

Generally, such devices comprise an elongated flexible element orline-mass formed into an endless or closed loop, a guide in which aportion of the loop is mounted so that the loop is freely movablesubstantially longitudinally along the guide, and means for moving theloop through the guide with speed suflicient to cause the portion of theloop not constrained by the guide to erect into a substantially rigidstructure. In a preferred embodiment the means for moving the loop is inthe form of means for introducing a fluid flow into the guide with asufficient mass velocity component directed along the longitudinal axisof the portion of the loop therein such that passage of fluid into theguide will propel the loop at the desired speed.

Other objects of the invention will in part be obvious and will in partappear hereinafter. The invention accordingly comprises the apparatuspossessing the construction, combination of elements, and arrangement ofparts and the method comprising the several steps and relation of one ormore such steps with respect to each of the others, all of which areexemplified in the following detailed disclosure, and the scope of theapplication of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the presentinvention, reference should be had to the following detailed descriptiontaken in connection with the accompanying drawings wherein:

FIG. 1 is an elevational view in cross-section through a simpleembodiment of the invention.

FIG. 2 is an elevational view in cross-section through yet anothermodification of a device embodying the principles of the presentinvention.

Referring now to FIG. 1, there is shown an embodiment of the presentinvention comprising guide means in the form of U-bent, hollow tube 20.An ingress end 22 of tube 20 preferably is flared internally and has arounded lip such as is provided by ring flange 24. The other or exit end26 of tube 20 need only be "simply open.

Flexible loop 28 is positioned so that a portion thereof extends throughtube 20, loop 28 being dimensioned in cross-section so as to be freelymovable through the tube. Loop 28, in the form shown in FIG. 1, issimply a beaded string or chain, the beads preferably being formed ofsome light-weight material such as synthetic polymers, light or hollowmetals, e.g. aluminum, or the like.

The embodiment of FIG. 1 further includes means for introducing a fluidflow into tube 20 tangentially (i.e. so that a major component of itsflow direction is directed substantially along the longitudinal axis ofat least part of the loop in tube 20 and toward exit end 26). To thisend, there is included hollow tube 30 mounted, for example, on a convexportion of tube 20 and communicating with the interior of tube 20 sothat fluid introduced in open end 32 of tube 30 will flow into tube 20substantially entirely toward exit end 26.

In operation, fluid under pressure, such as orally expelled air or waterfrom a hose or the like, is applied to tube 30, entering therefore intotube 20 and discharging largely from exit end 26 of the latter. Becauseof the irregular surface of loop 28 provided by the beaded structure,the fluid flow through tube 20 drives loop 28 so that the latter movescontinuously through tube 20. When the loop is driven at sufficientspeed, the free portion of the loop (i.e. the loose part unconstrainedby tube 20) will extend into an elongated, apparently rigid,self-supporting configuration. The size of the loop, and therefore theextent to which it becomes self-supporting depends on a number offactors, e.g. the loop density, the cross-section diameter of the tube,the length of loop, the mass velocity of the fluid, the compliance ofthe loop, and others. These factors, however, are all quite variablewithin wide limits. Typically, the U-tube can have a bend radius ofabout 2 inches and an internal diameter of Mr". A beaded loop ofpolystyrene beads of diameter about 3 feet in circumference can bereadily driven in such a tube by an impinging airjet, at a speed ofabout 60 ft./ sec. The latter is more than suflicient to force the freeportion of the loop into a self-supporting, elongated configuration thatremains quite rigid regardless of the orientation of the axis of loopelongation with respect to gravity. The loop will remain erected, i.e.self-supporting, for a few seconds even after the driving fluid flow iscut off, demonstrating that its rigidity depends on its own motion andnot on support provided by the driving fluid.

It is believed that the phenomenon observed occurs because the beadstring or line-mass is under tension generated by its motion. For astring of density, p, moving at velocity, V, there is a tensile stress0., nearly independent of local curvature of the string, i.e.

Since the string cannot endure compression without collapsing, being tosome'extent compliant, then for the principles of the present string tobe self-supporting, o' must be greater than c In other words the kineticenergy of the line-mass must always exceed its gravitational potentialenergy for the loop to be in erection. The simple analysis does notexplain a number of curious properties that the standing loop exhibits,and which contribute toward the fascination that the device arouses inusers. For example, an impulse applied transversely of the line massadjacent exit end 26 appears to propogate at approximately the velocityof the string toward the ingress end 22 of the device. Thus the stringfollows translations of the device as if it were a rigid structure.Rotation of the device about the axis of elongation of the standingstring reveals effects which seem gyroscopic. Thus, if so rotated, thestring forms a double helix having a plurality of turns, although theupper bight of the loop tends to maintain its original orientation. Whenthe rotation of the U-bend is stopped, the upper bight appears toprecess, slowly turning and unwinding the helix until the loop againlies substantially in a single plane The extent to which ,'he structureof the present invention can be modified without essentially changingthe basic elements is illustrated in the embodiment of FIG. 2 whereinthe guide means comprises hollow tube 40 which has a bore which issubstantially straight rather than curved as in the structure of FIG. 1.Extending through the bore of tube 40 from ingress end 42 of the lattterto exit end 44, is a portion of flexible endless loop 46. The loop, inthis embodiment, is shown simply as an endless length of fibrousmaterial such as a cotton string, woolen yarn or the like, with atypical hairy or fibrous and therefore uneven surface. Loop 46 can bearslubs or the like in various colors if desired, provided however thatthe maximum diameter of the yarn is sufficiently less than the minimuminternal diameter of tube 40, thereby allowing the yarn to pass freelythrough the tube.

If the slubs are fairly uniformly distributed along the yarn, the motionof the yarn can produce a siren effect. Ingress end 42 of the tubepreferably is slightly flared and has rounded edges to prevent unduefriction between the edges of the tube and the incoming motion of theloop.

As drive means for impelling loop 46 through the tube, there is providedsecond hollow tube 48 mounted, as a mouthpiece or the like, so that theinterior of tube 48 communicates with the interior of tube 40. In theform shown, the longitudinal axis of tube 48 is positioned normally tothe longitudinal axis of tube 40, and it is, therefore, desirable toprovide means for redirecting a fluid flow entering tube 40 from tube 48so that the flow direction is substantially toward exit end 44 andtherefore has a component of mass velocity substantially along thelongitudinal axis of that portion of loop 46 positioned within tube 40.To this end, tube 40 preferably includes annular chamber 50 disposedaround its interior bore intermediate the ends of tube 40 and providingopening 52 along a substantially annular path into the bore of tube 40.Tube 48 opens directly into chamber 50. The portion of the bore of tube40 from the annular opening of chamber 50 to ingress end 42 has aslightly smaller diameter than the portion of the bore from the annularopening to exit end 44. Wall of chamber 50 surrounding the bore towardingress end 42 is preferably conical so as to present a surface cantedat an angle which, when struck by a fluid flow, will redirect the fluidflow through opening 52 into the bore of tube 40 and toward exit end 44.Tube 48 is disposed so that fluid flow therethrough will be thusredirected.

In operation, the device of FIG. 2 functions in much the same manner asthe device of FIG. 1. It will be appreciated, however, that because tube40 is straight it will not of itself provide any bend or bight in loop46. Nevertheless, when the line mass of loop 46 is driven through thetube, the loop will form a long elongated, self-supporting structurewith end bends. Because the loop in this embodiment is quite light inweight, a substantial length up to several feet can readily be driveninto erection with lung-power and maintained in its rigid state forseveral seconds. If one desires to use compressed gas sources such ascarbon dioxide or tetrafluorethylene bottled under high pressures, loopsof twenty or more feet long can readily be maintained in erection formuch longer periods.

It will be apparent that a number of other modifications can readily bemade without altering the basic inventive concepts, For example, theflexibility of the loop does not preclude the quality of elasticity.Thus, the loop it formed, for example, of an elastically extensibleyarn, when placed in its free standing mode will tend to elongateconsiderably. Although as described, the force driving the loop isderived from a fluid flow, other driving forces can be employed, forexample a friction drive from a wheel rotated by spring forces. Andwhile the device as hereinbefore described is particularly useful as anovel interesting toy, its principles are susceptible of many otherapplications.

Since certain changes may be made in the above apparatus withoutdeparting from the scope of the invention herein involved it is intendedthat all matter contained in the above description or shown in theaccompanying drawing shall be interpreted in an illustrative and not ina limiting sense.

What is claimed is:

1. An erection device comprising, in combination,

an elongated flexible element forming a closed loop substantiallyincapable of being self-supporting in static condition;

guide means providing a constraining path for only a minor portion ofsaid loop so that said portion is movable relative to said guide meanssubstantially along its longitudinal axis in said path, the remainder ofsaid loop being unconstrained; and

means for propelling said portion along said path relative to said guidemeans at a speed, as substantially the sole cause, suflicient to erectsaid unconstrained remainder of said loop into a substantially rigidstructure.

2. An erection device as defined in claim 1 wherein said elongatedelement has an irregular surface.

3. An erection device as defined in claim 1 wherein said guide meanscomprises a first hollow tube through which said portion is movable, and

said means for propelling comprises means for introducing a fluid flowinto said tube so that said fluid flow is directed substantially towardone end of said tube and said fluid flow serves to drive said loop.

4. An erection device as defined in claim 3 wherein said first tube isbent in an arcuate segment and said means for introducing said fluidflow comprises a second hollow tube communicating with said first tubetangentially to the arc of the latter.

5. An erection device as defined in claim 3 wherein said first tube issubstantially straight and said means for introducing said fluid flowcomprises a chamber having a substantially annular opening into theinterior of said first tube, and a second tube communicating with saidchamber,

said chamber including a wall portion thereof disposed for redirecting afluid flow from said second tube into said first tube substantiallytoward one end of the latter.

6. An erection device as defined in claim 3 wherein said elongatedelement is a beaded string.

7. An erection device as defined in claim 3 wherein said elongatedelement comprises a fibrous yarn.

8. An erection device as defined in claim 1 wherein said element andsaid means for propelling are selected so that the speed that can beimparted to said loop will provide a tensile stress to said loop inexcess of the compressive stress in said loop due to gravity when saidloop is erected.

References Cited UNITED STATES PATENTS 6 FOREIGN PATENTS 639,136 11/1936Germany. 662,613 7/ 1938 Germany.

5 OTHER REFERENCES Advertisement circular entitled Phony Squirts published in 1965 by H. Fishlove and Co., 712-20 Nortl Franklin St.,Chicago, 111. 60610.

10 ANTON O. OECHSLE, Primary Examiner.

F. BARRY SHAY, Examiner. A. W. KRAMER, Assistant Examiner.

1. AN ERECTION DEVICE COMPRISING, IN COMBINATION AN ELONGATED FLEXIBLEELEMENT FORMING A CLOSED LOOP SUBSTANTIALLY INCAPABLE OF BEINGSELF-SUPPORTING IN STATIC CONDITION; GUIDE MEANS PROVIDING ACONSTRAINING PATH FOR ONLY A MINOR PORTION OF SAID LOOP SO THAT SAIDPORTION IS MOVABLE RELATIVE TO SAID GUIDE MEANS SUBSTANTIALLY ALONG ITSLONGITUDINAL AXIS IN SAID PATH, THE REMAINDER OF SAID LOOP BEINGUNCONSTRAINED; AND